I made a stupid mistake. In one of my project I used a adp3334acp to regulate 7v input power to 6v output. according to the datasheet of adp3334, "the thermal pad is attached to the die substrate, so the thermal planes that the vias attach the package to must be electrically isolated or connected to VIN. Do NOT connect the thermal pad to ground." But in my design, I carelessly attached the thermal pad to the ground. I thought this circuit will not work and I had to re-design it. But surprisingly, it did work! I got a 6V output from the 7V input.
My question is: should I follow the datasheet and connect the thermal pad to VIN or let it float? If I connect the thermal pad to ground, what will happen?
Attached is my circuit: